Background Art In general, in an automobile equipped with a manual transmission, a driver has to step on a clutch pedal in order to change the speed of the automobile and stop the automobile, which may cause inconvenience and trouble to the driver. Therefore, the driver may feel extremely tired when the driver drives the automobile having a manual transmission for long time or on a road in a traffic jam.

Especially in the case of a large automobile of at least five tons, too heavy load is necessary in operating the clutch, so that the tiredness the driver feels may cause a severe problem. In order to solve such a difficulty as described above, apparatuses of operating a clutch by means of hydraulic pressure have come into wide use. However, such hydraulic apparatuses as described above consume relatively large power, thereby largely reducing the power of the engine.

Therefore, the apparatuses as described above inevitably

require an engine of high horse power, which is a main factor largely increasing the price of the automobile.

In more detailed description, a transmission, an apparatus for transmitting power in an automobile, is largely classified into three kinds of transmissions, including a manual transmission, an automatic transmission, and a semi-automatic transmission. Among those three kinds of transmissions, the semi-automatic transmission has been developed for a gear shifting operation in a large commercial vehicle such as a large truck and a large trailer, and is now classified into an electro-pneumatic shift (EPS) transmission and a torque converter-shift clutch, in which a hydraulic torque converter and a mechanical clutch are combined.

In this case, the EPS transmission is a semi- automatic transmission, which is advantageous in that the EPS transmission is capable of carrying out a multiple-speed transmission (six gear steps to sixteen gear steps), has a high transmission efficiency, and uses a gear train which is relatively less expensive and is capable of supporting a relatively large load in comparison with an epicyclic gearing. In the EPS transmission, a mechanical shift linkage interconnecting a gear shift lever and a transmission body is replaced by an electronic pneumatic shift linkage. Therefore, when the driver operates a gear shift lever to shift gear by means of a magnet valve and a servo cylinder, the servo cylinder is operated by control electronics, so as to carry out the gear shifting operation.

Meanwhile, in the torque converter-shift clutch uses an electromagnetic control valve, in which a friction clutch is located between a torque converter

and a mechanical transmission, so that the clutch is automatically switched according to the operation of the shift lever. Therefore, in the transmission of the torque converter-shift clutch type, the friction clutch is electrically switched according to the operation of the shift lever without a clutch pedal, so that a semi- automatic gear shifting operation is carried out.

The semi-automatic transmission as described above has both the power of the manual transmission and the convenience of the gear shifting operation in the automatic transmission. Moreover, in comparison with the automatic transmission, the semi-automatic transmission has a simpler construction, so that it can be manufactured with lower expense. Further, the semi- automatic transmission has less trouble than the automatic transmission. Therefore, the semi-automatic transmission is now being developed to be suitable for general passenger cars.

However, it is a general opinion that the automatic and the semi-automatic transmissions as described above are improper for commercial vehicles in that they remarkably reduce the power of the engine in spite of the high additional expenses for the transmissions. Therefore, it is currently a prominent trend that the automatic and the semi-automatic transmissions are not employed in order to ensure a stable power of the engine.

In more detailed description, in the case where the automatic and the semi-automatic transmissions as described above are additionally installed to already delivered commercial vehicles, the power or the engine output of the commercial vehicles is remarkably reduced.

Therefore, there has been an earnest request for a clutch construction capable of functioning as both a manual transmission and a one-touch semi-automatic transmission, which not only can reduce load applied to the driver's leg during the driving of the automobile, but also can enable the clutch operation to be precisely controlled and prevent the power of the engine from being deteriorated.

Disclosure of the Invention Therefore, the present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an apparatus for operating a semi-automatic clutch for an automobile, which enables the gear shifting operation to be easily carried out through a one-touch operation by means of electric and pneumatic force.

It is another object of the present invention to provide an apparatus for operating a semi-automatic clutch for an automobile, in which gear shifting operation can be easily carried out through a one-touch operation by means of electric and pneumatic force without manually operating a clutch pedal according to a driver's necessity while the apparatus employs the natural mechanical construction of the existing manual transmission.

It is another object of the present invention to provide an apparatus for operating a semi-automatic clutch for an automobile, in which all operations from the starting of the engine to the gear shifting operation during the driving can be carried out semi- automatically through air quantity control means of a

switch construction, even without using the clutch pedal at all.

According to an aspect of the present invention, there is provided an apparatus for operating a semi- automatic clutch for an automobile, the apparatus comprising: at least one master cylinder for operating a clutch between an engagement state and a release state for a gear shifting operation of the automobile; a hydraulic cylinder operated by hydraulic pressure, so as to operate the master cylinder ; a hydraulic tank connected to the hydraulic cylinder through a fluid channel, so as to apply the hydraulic pressure to the hydraulic cylinder ; an electronic control valve for controlling supply of the hydraulic pressure from the hydraulic tank to the hydraulic cylinder by opening and closing the fluid channel; and a switch for operating the electronic control valve, wherein, when the switch is ON, the electronic control valve opens the fluid channel from the hydraulic tank to the hydraulic cylinder, so as to enable the hydraulic pressure to be applied from the hydraulic tank to the hydraulic cylinder, while the electronic control valve closes the fluid channel when the switch is OFF.

It is preferred that fluid utilized in the apparatus is air, and the hydraulic cylinder, the hydraulic tank, the hydraulic pressure controller, and the hydraulic pressure are respectively an air cylinder, an air tank, a pneumatic controller, and air pressure.

It is more preferred that the switch comprises a switch body shaped like a container one end of which is open, a switch button inserted in the switch body in a shape of a push button, and a spring applying a one-way

force in an outward direction of the switch body to the switch button, and an electric contact is arranged on each of a bottom surface of the switch button and an inner bottom surface of the switch body, so that the electronic control valve is operated when the switch button is pressed to make the two electric contacts be in contact with each other.

The air cylinder may have a suction port and an exhaust port, and the apparatus may comprise a first pneumatic controller connected to the electronic control valve and the suction port, and a second pneumatic controller connected to the electronic control valve and the exhaust port.

Further, the switch may have an air pressure control chamber defined by an inner surface of the switch body and a lower surface of the switch button, and the second pneumatic controller comprises a first air guide tube interconnecting the electronic control valve and the air pressure control chamber, and a second air guide tube interconnecting the air pressure control chamber and the exhaust port.

According to another aspect of the present invention, the apparatus may further comprise a manual clutch operation assembly, which includes a clutch pedal and a pedal lever integrally connected with the clutch pedal, so that the pedal lever operates the second actuating rod of the second master cylinder to convert the clutch into the release state when the clutch pedal is pressed.

Brief Description of the Drawings The foregoing and other objects, features and

advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: FIG. 1 is a constructional view schematically showing an apparatus for operating a semi-automatic clutch for an automobile according to an embodiment of the present invention; FIG. 2 is a sectional view showing the construction of a switch having an air quantity control function, which is employed in the apparatus shown in FIG. 1; FIG. 3 is a constructional view schematically showing an apparatus for operating a semi-automatic clutch for an automobile according to another embodiment of the present invention; and FIG. 4 is a constructional view schematically showing an apparatus for operating a semi-automatic clutch for an automobile according to another embodiment of the present invention.

Best Mode for Carrying Out the Invention Reference will now be made in detail to the preferred embodiments of the present invention.

FIG. 1 is a constructional view schematically showing an apparatus for operating a semi-automatic clutch for an automobile according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the construction of a switch having an air quantity control function, which is employed in the apparatus shown in FIG. 1.

In the apparatus for operating a semi-automatic

clutch for an automobile according to an embodiment of the present invention, when a treading force applied to a clutch pedal 16 is transmitted through a pedal lever 26 and an actuating rod 25 to a master cylinder 15, a clutching operation equal to the gear shifting operation utilizing a gear shift lever 20 is carried out by means of electric power of a battery together with air pressure of an air tank 11 which is generally installed in a large automobile.

In the apparatus for operating a semi-automatic clutch for an automobile according to an embodiment of the present invention, the air pressure is transmitted from the air tank 11 through an electronic control valve 12 to an air cylinder 14, so as to move an air cylinder lever 24 forward and backward, thereby operating the master cylinder 15. In this case, the air cylinder lever 24 is arranged in connection with the pedal lever 26 of the clutch pedal 16, so that they cooperate with each other. The electronic control valve 12 delivers the air pressure of the air tank 11 to a chamber in the reciprocating air cylinder 14, so as to move an actuating bar of the air cylinder 14 forward and backward. The electronic control valve 12 is operated by a solenoid and returned by a spring.

In this case, the air cylinder lever 24 connected to the actuating bar of the air cylinder 14 is pivotally fixed by a pivot pin 18 while being spaced a predetermined distance apart from the actuating rod 25, likewise the pedal lever 26 connected to the clutch pedal 16. Reference numeral 17 not described above designates an oil tank communicating with the master cylinder 15.

Further, in the apparatus of the present invention, a switch 21 is mounted to the gear shift lever 20, so as to regulate the electric power of the battery applied to the electronic control valve 12, thereby operating the air cylinder 14. The switch 21 employs a construction of a push button which is operated when it is pressed while being restored to its initial position by a spring force when it is released.

It is preferred that the switch 21 is disposed at a grip portion of the gear shift lever 20 so that the switch 21 can be operated simultaneously with the gear shifting operation.

As shown in FIG. 2, the switch 21 includes a switch body 21a shaped like a container one end of which is open, a switch button 21b inserted in the switch body 21a to form a shape of a push button, and a spring 21c applying a one-way force in an outward direction of the switch body 21a to the switch button 21b. An electric contact is arranged on each of a bottom surface of the switch button 21b and an inner bottom surface of the switch body 21a, so that the electronic control valve 12 is operated when the switch button 21b is pressed to make the two electric contacts be in contact with each other. Further, an air pressure control chamber 211 is defined by the inner surface of the switch body 21a and the lower surface of the switch button 21b, so that the volume of the air pressure control chamber 211 varies according to the position of the switch button 21b.

Moreover, at least one pneumatic controller 13 is disposed between the electronic control valve 12 and the air cylinder 14. The pneumatic controllers 13 may be respectively connected with a suction port 141 and an

exhaust port 142 for reciprocating a piston rod 14b of the air cylinder 14. In this case, it is preferred that the pneumatic controller 13 connected with the exhaust port 142 includes first and second air guide tubes 12a and 14a connected with the switch body 21a, so that the volume of the air pressure control chamber 211 and the quantity of air passing through the first and the second air guide tubes 12a and 14a can be controlled according to the location of the contact P arranged on the bottom surface of the switch button 21b. In this case, such a construction of the pneumatic controller 13 connected with the exhaust port 142 as described above enables a semi-clutch state, thus allowing the vehicle to be smoothly started.

In other words, the switch button 21b having a contact P formed at the bottom of the switch button 21b is inserted in the switch body 21a having another contact P formed at an inner surface of the switch body 21a, so as to regulate the electric power of the battery. Also, the first and the second air guide tubes 12a and 14a communicating with the electronic control valve 12 and the air cylinder 14 are connected to both side walls of the switch body 21a opposed to each other, so as to effectively control the quantity of air supplied through the electronic control valve 12 to the air cylinder 14. Further to the above construction, the switch button 21b may have a pin (not shown) disposed at the lower end of the switch button 21b, which prevents the switch button 21b from being separated from the switch body 21a.

It is preferred that the electronic control valve 12 is a solenoid valve, which is operated so as to

enable air pressure to be supplied from the air tank 11 to the air cylinder 14 when the switch button 21b is pressed to make the electric contacts P come into contact with each other. When the electric contacts P are separated from each other, a biased spring force urging the electronic control valve 12 to close the fluid channel from the air tank 11 to the air cylinder 14 is applied to the electronic control valve 12.

In the meantime, the master cylinder 15 is connected to the oil tank 17 and contains oil supplied from the oil tank 17. Further, the master cylinder 15 includes the actuating rod 25, which reciprocates in the master cylinder 15 so as to apply pressure to the oil in the oil tank 17, thereby operating the clutch between engagement and release states by means of an actuator 23. The air cylinder 14 includes a piston rod 14b, which is reciprocated in the air cylinder 14 by the air pressure supplied through the electronic control valve 12 from the air tank 11. The actuating rod 25 is operated by the piston rod 14b.

The piston rod 14b of the air cylinder 14 is connected to the air cylinder lever 24 which is pivotable about the pivot pin 18. When the piston rod 14b is operated by the air pressure, the air cylinder lever 24 pivots about the pivot pin 18, so as to push the actuating rod 25, thereby switching the clutch into the release state.

In the apparatus for operating a semi-automatic clutch for an automobile according to an embodiment of the present invention having the construction as described above, the manual clutching operation is the same as that in the conventional apparatus, in which the

master cylinder 15 is operated to disengage the clutch when the clutch pedal 16 is trod so that the pedal lever 26 is pivoted. Meanwhile, when a driver feels tired at his or her leg for a long-time driving or for any other reason, the driver can press the switch button 21b disposed at the gear shift lever 20, so that the air pressure of the air tank 11 is instantly transmitted to the air cylinder 14, so as to pivot the air cylinder lever 24, thereby operating the master cylinder 15, which makes the clutch be disengaged. In the meantime, when the driver releases his or her hand from the switch button 21b after the operation of the gear shift lever 20 is completed, the switch 21 becomes off, so that the electronic control valve 12, the air cylinder 14, and the master cylinder 15 are restored to their original states.

In the case where the switch 21 performs the function of the pneumatic controller also as shown in detail in FIG. 2, not only pressing the switch button 21b has the same effect as stepping on the clutch pedal 16, but also, by gradually releasing the pressed switch button 21b, the volume of the air pressure control chamber 211 and the quantity of air passing through the first and the second air guide tubes 12a and 14a connected to both sides of the switch body 21a can be gradually changed, so that the semi-clutch state is achieved. Therefore, all operations from the starting of the engine to the gear shifting operation during the driving can be carried out semi-automatically even without using the clutch pedal at all.

FIG. 3 is a constructional view schematically showing an apparatus for operating a semi-automatic

clutch for an automobile according to another embodiment of the present invention.

The apparatus according to the present embodiment includes two master cylinders 15 operated by the air cylinder 14, an electronic control valve 22 for selecting one of the operating pressures of the two master cylinders 15, and the actuator 23 for operating the clutch by means of the selected operating pressure.

In the apparatus, in addition to the master cylinder 15 connected to the clutch pedal 16, another master cylinder 15 operated by the air cylinder 14 is also arranged. The electronic control valve 22 selectively applies the hydraulic pressure from the two master cylinders 15. In this case, the electronic control valve 22 is a hydraulic valve, while the electronic control valve 12 in the previous embodiment is a pneumatic valve. Of course, the electronic control valve 22 is operated by means of the switch 21 mounted to the gear shift lever 20. The actuator 23 converts the hydraulic force to a mechanical force for operating a link.

In other words, in the apparatus for operating a semi-automatic clutch of FIG. 3, when the clutch pedal 16 is trod so that the master cylinder 15 is operated, the hydraulic force is applied through the electronic control valve 22 to the actuator 23, so that the mechanical force is applied to thereby operate the clutch. In the meantime, when a driver wants to operate the clutch by means of the switch button 21b of the gear shift lever 20 because of such reasons as tiredness during driving, he or she may press the switch 21. At the moment, as described above, the air pressure of the air tank 11 is transmitted to the air cylinder 14, so as

to move the piston rod 14b linearly, thereby operating the master cylinder 15, which results in disengagement of the clutch. When the driver releases his or her hand from the switch button 21b after the operation of the gear shift lever 20 is completed, the switch 21 becomes off, and the electronic control valve 12, the air cylinder 14, and the master cylinder 15 are restored to their original states.

In comparison with the apparatus of FIG. 1, although it has a somewhat more complicated construction, the apparatus of FIG. 3 is more advantageous in that a larger space can be secured in the driver's seat and misoperation can be prevented because the air cylinder lever 24 installed in driver's seat of the apparatus of FIG. 1 is not necessary in the apparatus of FIG. 3. However, the two apparatuses are the same in an aspect that the gear shifting operation can be easily carried out only by pressing the switch 21.

FIG. 4 is a constructional view schematically showing an apparatus for operating a semi-automatic clutch for an automobile according to another embodiment of the present invention. In the apparatus according to the present embodiment, the air cylinder lever 24 and the pedal lever 26 are independently connected to the master cylinder 15, so that one lever has no effect on the operation of the other lever. The apparatus of the present embodiment has a construction similar to that of the apparatus shown in FIG. 1, except that the air cylinder lever 24 and the pedal lever 26 are arranged nearly horizontally in the apparatus of FIG. 3 while they are arranged vertically in line with each other in

the apparatus of FIG. 1. Also, in the apparatus of the present embodiment, the air cylinder lever 24 and the pedal lever 26 are separated from each other, so that they can be operated independently to each other.

That is, when the switch 21 is pressed so that the master cylinder 15 is operated, the air cylinder lever 24 is pivoted, and yet the pedal lever 26 of the clutch pedal 16 is not pivoted together with the air cylinder lever 24 but is maintained in its position, which is advantageous in a view of a safe driving of the automobile.

As apparent from the above description, the apparatus for operating a semi-automatic clutch for an automobile according to the present invention can be directly installed to an existing transmission, so as to enable the gear shifting operation to be performed semi- automatically in one touch mode, thereby allowing the gear shifting operation to be carried out more easily.

The pneumatic system and electric power necessary in the apparatus of the present invention not only may be easily obtained in the existing automobile, but also do not add difficulty in the wiring and piping of the automobile.

Further, since the semi-automatic gear shifting operation can be selectively carried out according to the driver's necessity, the fuel expenses for driving the automobile is not largely increased.

Industrial Applicability As can be seen from the foregoing, in the apparatus for operating a semi-automatic clutch for an automobile according to the present invention, the gear

shifting operation can be easily carried out in a one touch mode by means of electric power and pneumatic power according to the driver's necessity without manually operating a clutch pedal.

While this invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments and the drawings, but, on the contrary, it is intended to cover various modifications and variations within the spirit and scope of the appended claims.